This invention broadly relates to systems and methods for capturing and presenting visual information. More particularly, the invention relates to systems and methods for allowing a viewer to see images in the same manner that they are seen by another viewer. While not limited thereto, the systems and methods are applicable for training an individual who will be required to make ostensibly subjective visual determinations to make those determinations in the same or similar manner as made by an expert. Other applications include entertainment, research, therapy and the creation of art.
The visual system of the human eye can be considered to consist of an optical component which focuses a scene upon the retina, and a neural processing component which detects visual features of the scene and assembles a perception embedding meaning. Extensive research has demonstrated that the neural system, from the retina on, processes what is in essence a series of stills to create a perception which contains apparently continuous motion and change. Effectively, then, the vision system operates in a manner quite analogous to a moving picture (movie) which is comprised of a sequence of still photographs.
The neuromuscular system of the eye operates to cause the eye to track points of interest in the visual field, i.e., the scene, and to focus the points of interest in the fovea, the small region of extremely high resolving capacity in the retina. The tracking of the eye, however, is not continuous. Instead, tracking is in the form of a sequence of extremely quick jumps (saccades), which separate longer periods (fixations) during which the eye does not move and the focused scene is fixed in place on the retina. The vision system appears to be sensitive to information only during fixations. Information presented during saccades is not perceived, while the same information presented for the same duration during a fixation period is perceived.
Besides the saccadic movement of the eye, there is another finer level of eye movement called nystagmus, which continuously makes low amplitude jumps essentially at random. The effect of nystagmus is to cause the point focused in the fovea of the retina to jitter, while still staying within the high resolution area. The primary purpose of nystagmus appears to be to prevent saturation and exhaustion of individual receptor cells in the retina. Subsequent post-retinal neural processing completely removes the motions induced by nystagmus from the perceived scene. Motions induced by saccades are largely removed as well, although, to a limited extent, the saccadic motion removal is under conscious control.
Certain well known research findings are key to the hereinafter described invention. See, e.g., Monty, Richard A. and Senders, John W., Eye Movements and Psychological Processes, John Wiley & Sons (1976). First by optical tracking of the eyeball it is possible to detect where within a scene an eye is gazing from saccade to saccade, and even from jitter to jitter of nystagmus. See, e.g., Frecker, R. C. et al, High-Precision Real-Time Measurement of Eye Position Using the First Purkinje Image, Theoretical and Applied Aspects of Eye Movement Research, Elsevier Science Publishers B.V. (1984). Second, individuals are found to use idiosyncratic scanning patterns as they saccade over a scene. The patterns apparently depend on the scene content and the emotional state and predispositions of the subject. Third, a device which tracks eye motions at the saccade or nystagmus level is commonly called a tracker and such trackers are well known and in wide commercial use today, for example in aircraft simulators. Fourth, it is known that a tracker can be coupled to an optical apparatus called a fixer which projects a spot of light or other visual object and moves the spot in precise step with the eye movements detected by the tracker in such a way that the spot is always focused on exactly the same place on the retina, i.e. the fovea, regardless of the motions of the eye. Subjects find that the spot rapidly drops from perception and becomes effectively invisible. Fixers are in commercial use today, for example in laser surgery of the retina.